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You are not logged in. #1 20060204 05:37:10
A problem!!!!Heres the question: #2 20060204 08:17:50
Re: A problem!!!!The problem seems simple enough, however I am having trouble visualizing what is happening here. The description of the wiper has left me baffled. It probably isn't your fault though as I am often baffled by thy simplest things. #5 20060205 03:54:26
Re: A problem!!!!Good picture johny. Also there are more complications coming up. We will need to know the rate at which the rubber is changing in length. Is this a constant rate of change? In other words we a radius that is changing here and it needs to be defined. #7 20060205 04:57:02
Re: A problem!!!!
But then the lenght of the rubber is 30. In your diagram, it is only 20. Last edited by Ricky (20060205 04:57:28) "In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..." #9 20060205 05:38:50
Re: A problem!!!!I can't tell what part of the wiper is fixed to the blade. Top, bottom, or center? I tried resolving the y functions given with trigonomic functions and couldn't figure it out. Last edited by irspow (20060205 05:40:22) #11 20060205 06:05:32
Re: A problem!!!!That can't be true. Then the distance from the top of the arm to the top of the blade at 0° would be 5 and not the 10 shown in the diagram. It is now seeming a little funny how these little details can be huge obstacles in what would otherwise be a simple calculation. Last edited by irspow (20060205 06:07:33) #12 20060205 06:32:27
Re: A problem!!!!
If that line is directly out of your book, then I suggest you get another book... "In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..." #13 20060205 06:37:10
Re: A problem!!!!That is kind of where my thinking has gone. The book probably made some strange assumption and that the readers would make the same also without specifically stating what it was. I am from the U.S. and I don't know of any wipers that change in length here, so the entire premise is new to me. #14 20060205 06:39:45
Re: A problem!!!!
If that line is directly out of your book, then I suggest you get another book...
Ok, so we start at +40, not +30. Then everything comes together.
What this means is that the distance from the vertex and the start of the rubber is constantly changing. The equations above show this distance changing, it's nothing extra. Just an explanation. "In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..." #16 20060205 06:50:20
Re: A problem!!!!It is nice that you now understand all of this Ricky, but how do you know the limits of integration for y1 and y2 taking into account that the blade's length is changing by 10 centimeters. Last edited by irspow (20060205 06:52:56) #17 20060205 06:58:23
Re: A problem!!!!
The equations describe that change of 10 centimeters. "In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..." #18 20060205 07:02:26
Re: A problem!!!!To sum up for Jonny, the answer (so far) is: You can use what irspow said to simplify the integration, if you wish. Last edited by Ricky (20060205 07:02:37) "In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..." #19 20060205 07:06:52
Re: A problem!!!!Sooo, what are the proper limits of integration for y1 and y2? I am thickheaded and am still confused. If you know them then you could post the area for johny. Last edited by irspow (20060205 07:08:17) #21 20060205 07:20:55
Re: A problem!!!!Oh, ok, I misunderstood you before irspow. But I'm still not sure what you mean now:
What do you mean limits for y1 and y2? My solution never integrates y1 and y2. It integrates y1  y2, is that what you mean? "In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..." #23 20060205 08:25:22
Re: A problem!!!!My problem is in post #14 it was stated that the top of the wiper blade is where the change in length occurred. If that is true then the blade is fixed at the bottom of the arm. Thus the radius of y2 would always be 40 from the vertex. #24 20060205 08:39:48
Re: A problem!!!!Actually, I just ran through the trigonomic relations regarding the situations with the blade fixed at the top and y1 and they also didn't match. I also revisited the situation for fixed bottom and it too failed to create a match for y1. I cannot see what is going on here. Last edited by irspow (20060205 08:48:57) #25 20060205 16:24:32
Re: A problem!!!!Is the wiper blade centered on the end of the wiper arm? igloo myrtilles fourmis 